Due to their exceptional mechanical properties, carbon nanotubes are used in high performance structural and multifunctional nanostructural materials and devices. Due in part to the nanostructures of carbon nanotubes, strong interactions, such as van der Waals forces, can occur between nanotubes. As a result, achieving good tube dispersion, desirable tube alignment, and high tube loading in nanocomposites can be exceptionally difficult, if not impossible, when conventional manufacturing methods are used.
Many high performance new nanocomposites having electrical conductivity and/or thermal conductivity could be realized by using a buckypaper or membrane (5-200 μm in thickness) having controlled nanostructures (i.e., dispersion, alignment and/or loading). These buckypapers also could be used to impart macroscale materials with one or more of the advantages associated with nanocomposites.
Although buckypapers can be formed by filtering a suspension of carbon nanotubes (CNTs), the filtration step usually is a slow process due to the nanoscale size of the carbon nanotubes, and nanoscale porous nanostructures of their networks in buckypapers. Also, it can be difficult to produce a buckypaper on a large scale that has consistent properties throughout its structure. Attempts have been made to devise a continuous process for making buckypapers, but the processes typically suffer from one or more disadvantages, including slow production rates, inconsistent quality, the inability to monitor buckypaper quality, the inability to align and/or crosslink the CNTs as part of an in-line process, or a combination thereof.
Although some continuous methods and systems for making buckypapers have been developed, there remains a need to improve these methods and systems. For example, the methods and systems could be designed to be easier to operate, provide more control over the properties of the resulting buckypapers, allow for in-line crosslinking and/or alignment of the CNTs, produce continuous buckypapers at a faster rate, and/or continuously monitor the qualities of the buckypapers.